Beyond conventional drying: improving the quality of dried Tremella fuciformis via a heat-integrated pretreatment

Hot-air drying (HAD) of Tremella fuciformis often results in poor rehydration capacity, yellowing, and long preparation times, which significantly reduce its industrial and consumer value. This study introduces a heat-integrated pretreatment (HIP) as a simple and viable strategy to improve the quality of dried T. fuciformis. The effects of HIP on water status, microstructure, and rheological behavior were systematically investigated via using low-field nuclear magnetic resonance (LF-NMR), magnetic resonance imaging (MRI), scanning electron microscopy (SEM), and rheological analysis. HIP effectively regulated water migration and preserved the polysaccharide matrix, which promots a controllable conversion of bound water to free water, thus facilitating more uniform dehydration. Among the tested conditions, HIP at 80 °C for 5 min increased the rehydration capacity by 74% compared with conventional HAD, while maintaining structural integrity and polysaccharide content. The treated samples exhibited brighter appearance, improved gelation behavior, and superior rehydration performance. These findings elucidate the mechanism by which HIP modulates polysaccharide-water interactions during drying and demonstrate its strong potential for manufacturing high-quality, quick-soak dried T. fuciformis products with enhanced physicochemical and structural properties.